Image decoding device, image coding device, and residual prediction device
Residual prediction poses a problem that deriving a residual involves a large amount of processing for generating two motion-compensated images and deriving a difference. Provided is a residual prediction device including a reference image interpolation unit that derives two residual prediction motion-compensated images, and a residual synthesis unit that derives a residual from a difference between the two residual prediction motion-compensated images and derives a predicted image by adding the residual to a motion-compensated image, in which the residual synthesis unit derives a predicted image by adding the residual to the motion-compensated image in a case where a target block size is greater than a predetermined size and derives the motion-compensated image as the predicted image in a case where the target block size is less than or equal to a predetermined size.
1. A residual prediction device comprising:
reference image interpolation circuitry that derives two motion-compensated images for residual prediction; and
residual synthesis circuitry that derives a residual using a difference between the two motion-compensated images and derives a residual compensation predicted image by adding the residual to a motion compensated image,
wherein the residual synthesis circuitry derives the residual compensation predicted image by adding the residual to the motion-compensated image in a case where color components of a target block are chroma components and a width of a prediction block is greater than 8, and derives the residual compensation predicted image from the motion compensated image in a case where the color components of the target block are the chroma components and the width of the prediction block is less than or equal to 8.
2. The residual prediction device according to claim 1 ,
wherein the residual synthesis circuitry derives the residual compensation predicted image by adding the residual to the motion-compensated image in a case where a color component of the target block is a luma component.
3. The residual prediction device according to claim 1 ,
wherein the reference image interpolation circuitry generates the motion compensated image and the residual compensation predicted image using bilinear interpolation.
4. An image decoding device comprising:
residual prediction index decoding circuitry that decodes a residual prediction index; and
the residual prediction device according to claim 1 ,
wherein the residual prediction index decoding circuitry decodes the residual prediction index in a case where a partition mode of a coding unit including the target block is 2N×2N and otherwise infers the value of the residual prediction index to be equal to 0.
5. An image encoding device comprising:
residual prediction index encoding circuitry that encodes a residual prediction index; and
the residual prediction device according to claim 1 ,
wherein the residual prediction index encoding circuitry encodes the residual prediction index in a case where a partition mode of a coding unit including the target block is 2N×2N and otherwise infers the value of the residual prediction index to be equal to 0.
6. An image decoding device comprising:
residual prediction index decoding circuitry that decodes a residual prediction index; and
the residual prediction device according to claim 3 ,
wherein the residual prediction index decoding circuitry decodes the residual prediction index in a case where a partition mode of a coding unit including the target block is 2N×2N and otherwise infers the value of the residual prediction index to be equal to 0.
7. An image encoding device comprising:
residual prediction index encoding circuitry that encodes a residual prediction index; and
the residual prediction device according to claim 3 ,
wherein the residual prediction index encoding circuitry encodes the residual prediction index in a case where a partition mode of a coding unit including the target block is 2N×2N and otherwise infers the value of the residual prediction index to be equal to 0.